The Mineralogy of Skarns of the Spurrite–merwinite Subfacies, Sanidinite Facies, Güneyce–ikizdere Area, Eastern Black Sea, Turkey

Abstract

Rare high-temperature and low-pressure contact-metamorphic assemblages are known to occur in the Güneyce-Ikizdere area, eastern Black Sea, Turkey. The emplacement of plutonic rocks of the calc-alkaline Rize batholith has caused the development of assemblages belonging to the spurrite-merwinite subfacies of the sanidinite facies. We provide compositional data for spurrite, rustumite, hillebrandite, tilleyite, cuspidine, vesuvianite, monticellite and gehlenite, and the secondary calc-silicates foshagite, dellaite, killalaite, bicchulite, hydroxylellestadite and two mineral species first discovered in these skarns, defernite and trabzonite. Our data point to the possible existence of a fluorine-rich variant of rustumite and a hydroxyl-dominant variant of cuspidine. These minerals are associated with familiar skarn minerals. The temperatures achieved are considered to be in the range 800-850°C on the basis of published phase-equilibrium results. The unusually high temperatures of contact metamorphism next to compositionally intermediate magmas may well reflect the presence of an underplating of basic magma in the vicinity and the efficient transfer of heat by the rising fluid phase. The relatively high concentrations of Cl and F encountered in these skarn assemblages are consistent with hydrothermal activity leading to Kuroko-type mineralization in this orogenic setting.

Nomenclature of wöhlerite-group minerals

“…2). Note that Taner et al (2013) reported cuspidine from the Güneyce–Ikizdere Region in Turkey, with an unusually low F content (1.36 apfu), which may correspond to a hydroxide equivalent. Finally, Krzątała et al (2018) reported from the Hatrurim complex, Israel, a ‘uranian cuspidine’ containing up to 0.64 U apfu, and only 0.98 F apfu.…”

“…Cuspidine, ideally Ca 8 (Si 2 O 7 ) 2 F 4 (Z = 2), was described by Scacchi (1876) from Monte Somma, Somma-Vesuvius complex, Italy. Cuspidine occurs in different geological environments such as skarns (Tilley, 1947;Taner et al, 2013), tuff ejecta (Federico and Peccerillo, 2002), pegmatitoid facies of venanzite (Bellezza et al, 2004a), calc-silicate xenoliths (Owens and Kremser, 2010), natrocarbonatite (Mitchell and Belton, 2004) and alkaline rocks (Andreeva et al, 2007). S.G.space group.…”

Scanning electron microscopy with energy dispersive spectroscopy and Raman and infrared spectroscopic study of tilleyite Ca5Si2O7(CO3)2-Y

“…The mineral was first described from Crestmore quarries, Riverside Co., California, USA [1]. Other occurrences were also reported from Flekkeren, Telemark, Norway [2]; Oravit ßa Skarns, Banat Mts, Caras-Severin Co., Romania [3] and Anakit Creek, Krasnoyarsk Territory, Eastern-Siberian Region, Russia [4,5]. Tilleyite forms in the contact metamorphic zone between igneous rocks and limestones, formed at low pressure and high temperature.…”

Ladik ve Esirağıl Alanı (Konya, Orta Anadolu) Yöresindeki Geç Silüriyen Erken Karbonifer Yaşlı Metakarbonatların Metamafik Dayklarla Kontak Metamorfizması

“…In Turkey, various contact metamorphic occurrences with various mineral assemblages have also been reported; e.g., the assemblage of wollastonite + garnet + An73 plagioclase + orthoclase + corundum + hercynite + hedenbergite-diopside ± scapolite in calcareous next to granitoids (Ortakoy-Aksaray; Kocak, 1993;Kocak and Leake, 1994), that of muscovite + biotite + garnet and forsterite+calcite around the Ahiçay-Elmalıçay granitoid in the Kastamonu granitoid belt (Boztuğ and Yılmaz, 1995), andalusite + corundum + K-feldspar assemblage around granodiorite in Eastern Pontides (Topuz, 2006), dio+gar±ep±qtz around Karadoru granitoid (Çanakkale, Aysal et al, 2006), and Spurrite + rustumite + hillebrandite + tilleyite + cuspidine + vesuvianite + monticellite + gehlenite one around tonalite Eastern Black Sea (Taner et al, 2013).…”